The present invention relates generally to the field of apparatus and methods for conveyor belt splice repair, and more particularly, to apparatus configured to mark the ends of a conveyor belt to be spliced along a bias angle by way of a multi-finger splice procedure.
Numerous types of conveyor belt splicing and repair methods are known. When belts come apart or tear in the field, skilled belt splicers are called upon to artfully cut the ends of the belt and rejoin them in the strongest manner possible. The belt splicing methods employed are typically decided based upon the material from which the belt is made, e.g., vulcanized rubber, elastomers, fabrics, as well as the demands of the application. Belt splices and reconnections may be “square,” i.e., perpendicular to the long axis of the belt, or “bias,” which deviates obliquely from square.
Biased vulcanized splices are most common. This is because bias vulcanized splices are resilient and outperform square splices in nearly every application. Also, studies show that a belt splice angled obliquely to the belt's long axis is able to more effectively displace torsional as well as both lateral and axial forces applied to the belt at the splice during operation. A bias splice is stronger and, therefore, more preferable than a square one. A bias splice is more difficult, however, since the splice is angled across the belt width while the cut splicing portions of the belt must remain parallel to the belt's long axis.
When measuring a belt straight across the width (square splice), the finger base and fingertip points, reference points which when marked onto the belt and connected delineate the splice cut lines, fall more or less uniformly across the belt. For the bias splice, however, fractions have to be calculated outwardly from the centerline of the belt so that the splicing portions of the belt maintain proper width when measured perpendicular to the long axis of the belt, which makes the mending of the belt uniform. Besides having to make arithmetic calculations in one's head, using a tape measure for this purpose is cumbersome and requires special dexterity while manipulating other hand tools. Errors too frequently occur as a result. Thus, numerous devices have been created and developed to aid in delineating splice lines, to free up hands, and to eliminate use of the tape measure. Each, however, has its shortcomings.
One such device utilizes chalk covered strings, e.g., chalk lines, stretched across a four-sided adjustable frame. The strings are attached at opposite ends of the frame so they can be individually raised until taught and released so as to snap down against the belt, which lies underneath the frame. Chalk deposited from the string forms a line on the surface of the belt. Clearly, chalk lines are replete with obvious problems, some of which include dirty wet conditions washing off the chalk, string breakage, messy chalk and faint undetectable lines.
Another prior art device includes a stencil in the shape of a parallelogram. Cutouts through the stencil correspond to finger base and fingertip points and positions as well as lines that connect the same when the stencil is moved into proper alignment. Once in position, operators apply spray paint or other marker through the cutouts, which makes the subject splicing delineations visible on the underlying conveyor belt. The paint tends to run and lines tend to clog, however, leaving inconsistent lines and requiring routine cleaning. Further, metal stencils are expensive, heavy to maneuver and have sharp edges that can cause personal injury and other damage when handled. Another problem is that each stencil is specific, and therefore limited to the measurements of its cutouts. Multiple stencils are therefore necessary for each belt specification, of which there are many. There is no universal stencil device.
Thus, it would be advantageous to provide an improved apparatus for accurately and conveniently marking conveyor belt splices. It would be advantageous if such a device was capable of eliminating the shortcomings identified above and could be used in any bias belt splicing procedure.